It's really easy to take for granted since most of us have never known any different.

My favourite was hot dog and sausage vendors in big US cities, especially New York, in the early 1900s ..... they would take semi rancid meat, mix it with lye or some chemical to reduce the stench and bacteria, then mix it with red food colouring .... a good batch was known as a mix that didn't make that many people sick.